Railway signaling system



R. M. LAURENSON RAILWAY SIGNALING SYSTEM July 4, 1933.

Filed April 16, 1932 mm m mm m mm W mm A s Mam & W Y J w J Q um i 5 l w kw NL $w w T M q mv Q 3 Patented July 4, 1933 v UNITED STATES PATENT OFFICE ROBERT M. LAURENSON, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH 8c SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA Application filed April 16,

My invention relates to railway signaling systems of the type involving light signals, and particularly to systems wherein the sig nals are of the Searchlight type. v

One feature of my invention is the provision of novel and improvedmeans for preventing a signal of this type from momentarily displaying a stop indication when the indication changes from caution to proceed or vice versa.

I will describe one form of signaling system embodying my invention, and will then point out the novel features thereof in the claim.

The accompanying drawing is a diagrammatic view showing one form of signaling system embodying my invention. v

Referring tothe drawing, the reference characters 3 and 3 designate the track rails of a railway track along which traffic normally inovesin the direction indicated by the arrow. These-rails are divided by insulated joints to form blocks of which only one complete block 1-2 is shown in the drawing. The blocks may be sub-divided to form track sections such as l1,'1 2, 22, etc. Each track section is provided with a track circuit comprising a battery connected across the rails adjacent one end of the section and a track relay connected across. the rails adjacent the other end of the'section" and. designated by the reference character Twvith a suitable distinguishing exponent.

Located adjacent the entrance end of each :block is a light signal designated by the reference character with a distinguishing exponent. Each signal in the form here shown is what'is known as a searchlight signal, comprisinga polarized armature 6 mounted to oscillate and controlled by-two windings 4 and 7 Winding 4: is constantly supplied with current of fixed relative polarity, the terminals of which are indicated by the reference charactersB and Of. Current of normal or reverse relative polarity is at times supplied to winding 7 by virtue of circuits which will be explained hereinafter.) The armature 6 carries three roundels G, Y and R,

arranged 'tocooperate with a lamp O in such manner that when the armature 6- is in itsv RAILWAY SIGNALING SYSTEM 1922. Serial No. 605,661.

middle position to which it is biased, roundel R will be in front of the lamp C. This is the condition of the signal when winding 7 is deenerg1zed. When winding 7 is energized by current of what I will term normal polarity, armature 6 will be swungto theright, so that roundel G will register with the lamp C. WVhen winding 7 is supplied with currentof what I will term reverse polarity, armature 6 will be swung to the left from its intermediate position, so that roundel Y will register with the lamp C. The signal will lndicate proceed, caution or stop according as roundel G, Y or R registers with the lam C when the lamp is lighted. The, lamp is shown above the roundels for purposes of illustration, but in actual practice it is placed directly behind the roundels. Operatively connected with, the armature-6 are two contacts 8 and 8", operated in such manner that 70 when the signal is in its stop position both contacts are open; when the signal is in its caution position contact 8 'is closed and contact 8 is open; whereas when the signal is in the proceed position contact 8" is closed and contact 8 is open. i

Each signal is controlled by a polarized line relay which is designated by the reference character A with a distinguishing exponent. Associated with each signal is an approach lighting relay L, a slow-releasing relay P, and an auxiliary relay X, the reference character for each of these relays being provided with a suitable distinguishing exponent.

As shown in the drawing, block 1-2 and the next block in advance are both unoccupied. Relay A is supplied with current of normal polarity by virtue of a circuit which passes from terminal B, through the 90 winding of relay L wire 45, front contact 47 of relay P front contact 49 of relay and'53, front contact 54 of track relay T wire 55, and front contact 56 of relay P to terminal 0. The polar c0ntacts-13 and '14 of relay A are therefore swung to the 9 left, and winding 7 of signal S is supplied with current of normal polarity, the circuit being from terminal B, through front contact of relay A polar contact 13, winding 7, and polar contact lt to terminal 0. Relay P is energized by virtue of a circuit which passes from terminal B, through front neutral contact 14: of relay A contact 3 of signal S and the winding of relay P to terminal 0. Auxiliary relay X is also ener gized by virtue of a circuit which includes front neutral contact 4 1 of relay A The armature 6 of signal S is now in such position that the proceed roundel G isin front of the lamp C, so that when this lamp becomes lighted the signal will indicate proceed.

I will now assume that a train moving toward the right approaches point 1. Owing to the fact that the track relay for the section in the rear of point 1 will be deenergized by the presence of such train, the approach lighting relay L will become deenergized. Lamp C of signal S will then be lighted by virtue of a circuit which passes from terminal B, through back contact of relay L front neutral contact 37 of relay A front contact 30 of relay X and lamp G to terminal 0. Signal S will there fore indicated proceed.

' When the train enters track section 11 it will deenergize track relay T and thereby open the circuit for relay A The opening of neutral contact 10 of relay A will open the normal circuit for Winding 7 of signal S I Lamp C'will be momentarily extinguished because of the opening offront neutral contact 37 of relay A The circuit for relay P will be opened at front neutral contact' lt of relay A, but during the time required for relay P to release, a holding circuit for winding f signal S will remain closed, this circuit being from terminal B, through front contact 18 of relay P polar contact 13 of relay A winding 7, and polar contact 14 of relay A to terminal 0. After "relay P releases, this holding circuit will *be opened so that'armature 6 will move to its middle position wherein roundel R registers with lamp 0. The release of relay P will also close a new circuit for lamp C, which circuit is from terminal B, through back contact lO'of relay L back contact 23 of relay P and lamp C to terminal 0. This circuit will, of course, not be closed unless approach lighting relay L is deenergized due to a following train approaching point 1. Relay X will be released due to the opening of contact 1 1 of rclayA When the train passes out of section 11 and into section 1 2, no change in the condition of the apparatus will occur, except that track relay T willrelease and track relay T will become energized. Relay A will remain deenergiz ed due to the fact that the front contacts 12 and l3 of track relay T will be open. Relay L will be deenergized all the time the train is in any part of block 12, so that lamp C of signal S will be lighted, with the result that this signal will indicate proceed.

lVhen the train enters section 22 it will release track relay T thereby deenergizing relay A and this in turn will cause relays P and X to become deenergized. 'Aft81 relay P releases, the armature of signal S will assume the stop position. As soon as track relay T releases, current of reverse polarity-will be supplied to relay A the circuit being from terminal B, through the winding of relay L back contact 54: of track relay wires 53 and 52, contact42 of each track relay T and T winding of relay A contact 43 of each track relay T and T wires 51 and 50, and back contact 419 of relay T to terminal 0. After relay P releases, current of reverse polarity will be supplied to relay A by virtue of a new circuit which passes from terminal B, through the winding of relay L wire 45, back contact 47 of relay P wire 52, contact 42 of each track relay T and T winding of relay A contact 43 of each track relay T and T wire 51, and back contact 56 of relay P to terminal 0. The reason for energizing relay A as soon as track relay T releases, is to avoid any possibility of a momentary false proceed indication by signal S such as might occur when a fast moving lightweight vehicle passes point 2; by virtue of the immediate energization of relay A it is unnecessary to. await the release of relay 1? before a possible temporary proceed circuit for signal S will become interrupted.

Relay A now being energized in the reverse direction, winding 7 of signal S will be supplied with current of reverse polarity, the circuit being from terminal B, through polar contact 14, winding 7 and polar contact 13 to terminal 0. The armature of signals will therefore move tothe caution-position, and contact 8 of this signal will become closed. Relay P will therefore become energized by a circuit which includes contact 14 of relay A and signal contact 8". Relay X will also become energized, and if-relay L is deenergized due to a train approaching point 1, lamp C will become lighted because of its circuit through contacts 37 and 30.

hen the train passes out of section 2-2 and into the next section ahead, no change will occur in the parts of the apparatus which are illustrated in the drawing except that track relay T will become energized.

VVhen the train leaves the section which begins at point 2*, relay A will become energized by current of reverse polarity, so that signal S will move to the caution position and relays P and X will become energized. As soon as relay P closes its front'contacts,

current of normal polarity will again be supplied to relay A so that signal S will move to the proceed position. Immediately upon the reversal of the polarity of the current supplied to relay A the front neutral contacts of this relay will release and will again pick up. Relay X will, of course, become deenergized due to the release of contact 44, and it Will again become energized when this contact closes. The period of time required for contact 30 of relay X to close after contact 44 closes, is such as to delay the lighting of lamp C for a period of time sufficient to insure that armature 6 has reached its proceed position. In signals of the searchlight type there is a small amount of rebound of the armature when moving from the caution to the proceed position or vice versa, during which rebound a' portion of the roundel R may register with the lamp C. The time period introduced by relay X issuflicient to prevent lamp C from becoming lighted until all inertia ofthe armature and other moving parts has been absorbed and the armature has come to rest in its proceed position. Relay X functions in a similar manner, of course, when the polarity of the current supplied to relay A changes from normal to reverse,

such, for example, as when a train backs into the block next in advance of block l'2, or enters such block from a siding.

Although I have herein shown and described only one form of apparatus of a signaling system embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claim without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

In combination, a light signal of the searchlight type, a polar relay for the control of said signal, a repeater relay controlled by a front neutral contact of said polar relay, a slow-releasing relay also controlled by a front neutral contact of said polar relay, a circuit for the lamp of said signal including a back contact of said slow-releasing relay, and a second circuit for the lamp of said signal including in series a front neutral contact of said polar relay and a front contact of said repeater relay.

In testimony whereof I aflix my signature;

ROBERT M. LAURENSON. 

